Dual piston unit for internal combustion engine



July 20, 1965 D. J. JOHANNSEN DUAL PISTON UNIT FOR INTERNAL COMBUSTION ENGINE Filed 001;. 17, 1963 2 M a M Y 0 B TEEIIIIL July 20, 1965 D. J. JOHANNSEN DUAL PISTON UNIT FOR INTERNAL COMBUSTION ENGINE Filed 061',- 17, 1965 2, Sheets-Sheet 2 Donald J Johannsen 1 N VEN TOR. Mm BY w United States Patent Office 3,195,420 Patented July 20, 1965 3,195,420 DUAL PISTON UNIT FOR INTERNAL COMBUSTIQN ENGINE Donald J. .lohannsen, Primghar, Iowa Filed Get. 17, 1963,Ser. No. 316,857 7 Claims. (Cl. 92--74) This invention comprises a novel and useful dual piston unit for internal combustion engines and more particularly pertains to an eccentric transmission mechanism for connecting the reciprocating pistons of an internal combustion engine to a rotating drive shaft.

The primary object of this invention is to provide an internal combustion engine of the opposed cylinder and piston type with an improved eccentric type transmission mechanism by which the pistons are connected to a common drive shaft.

A further object of the invention is to provide a transmission device in accordance with the foregoing object which shall enable opposed alined pistons to be rigidly connected together and to be attached to a single eccentric on the drive shaft.

A further object of the invention is to provide a transmission mechanism in accordance with the foregoing objects whereby the plurality of pairs of opposed pistons may be connected to the same drive shaft by an eccentric mechanism for each pair of pistons and wherein the mechanisms are so arranged that they may be assembled upon or removed from the drive shaft from one end thereof.

A still further object of the invention is to provide an internal combustion engine in accordance with the preceding objects and wherein the transmission mechanism connecting the pistons to the drive shaft shall be equally applicable to engines of the single-acting or double-acting type.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a fragmentary view in top plan showing the arrangement of two pairs of horizontally alined cylinders and pistons connected to a common drive shaft disposed therebetween, certain concealed parts being shown in dotted lines and certain parts being omitted and other parts being broken away and shown in section;

FIGURE 2 is a view in central vertical longitudinal section taken substantially upon the plane indicated by section line 2-2 of FIGURE 1 and showing the connection of a pair of opposed pistons to each other and to a common drive shaft, parts being broken away and shown in vertical section;

FIGURE 3 is an exploded perspective View of a portion of the drive shaft and of the eccentric mechanisms .associated therewith;

FIGURE 4 is a plan view showing a modified construction by which a double-acting piston unit is connected to a drive shaft through the transmission mechanisms of this invention; and,

FIGURE 5 is a View in horizontal section taken substantially upon the plane indicated by the section line 55 of FIGURE 4.

Referring first to FIGURE 1, the numeral designates generally an internal combustion engine of the type having a plurality of pairs of horizontally disposed cylinder and piston units positioned on opposite sides of a single drive shaft 12 disposed therebetween. Since the details of the engine structure in themselves form no part of the invention set forth and claimed hereinafter, a further showing and description thereof is deemed to be unnecessary. The cylinders are shown at 14 while the associated pistons are indicated at 16. The cylinder units are provided with theusual fuel supply and exhaust gas discharge means, not shown, and the combustible mixture is ignited therein as by a conventional igniting device such as a spark plug 18 from any conventional type of ignition system, not shown.

In accordance with this invention there is provided an eccentric mechanism for connecting each pair of opposed pistons to the same throw of the drive shaft 12. Referring now particularly to FIGURE 2 it will be observed that each piston is connected to a single rigid connecting rod indicated generally by the numeral 20. This connecting rod includes two complementary connecting rod sections each indicated by the numeral 22 and each of which is rigidly secured to an associated piston 16 as by means of the fastening bolts 24 as shown in FIGURE 2. At their outer ends, the two piston rod sections 22 are detachably secured together as by fastening bolts 26, these piston rod ends being enlarged to provide complementary halves of a cylindrical chamber 28. The two piston rod sections are thus clamped upon an eccentric mechanism which is journaled in the chamber 28 and which is connected to the drive shaft 12 whereby rotation of the shaft will result in reciprocation of the associated pair of pistons and vice versa.

It should be here noted that the piston rods are rigidly connected to the pistons and to each other so as to provide a rigid unit mounted for straight line motion along the axes of the two associated cylinder units. Any side thrust resulting from the arrangement is borne by the bearing engagement of the pistons 16 in their cylinder unit 14.

As will be apparent from FIGURE 1 in connection with FIGURE 3, the drive shaft 12 has a plurality of longitudinally spaced eccentric disks, two of which are shown at 30 and 32 and which are fixedly secured to the shaft. The disks are of different diameters, that shown at 30 being larger than that shown at 32 for a purpose to be subsequently apparent. However, mounted upon the disk 32 is a shell 34 whose outer diameter is equal to that of the other eccentric disk 30, as indicated by the dotted projection lines 36 of FIGURE 3 for comparative purposes.

A pair of eccentric rings 38 and 40 are provided which respectively are journaled upon and encircle the disk 30 and the disk 32 with its shell 34, these eccentric rings being of the same external diameter and being each received in one of the chambers 28 as previously mentioned. It will be observed that the ring 38 has a centrally disposed aperture 42 therein while the ring 40 has a similarly disposed aperture 44. These apertures are of the same diameter inasmuch as they are journaled upon the disk 30 and the combined disk 32 with its shell 34 which likewise have the same external diameters.

The arrangement is such that owing to the difference in the diameter of the disks 30 and 32, the eccentric ring 38 can be readily slid endwise over the disk 32 into its seated position upon the disk 30. Thereafter, the shell 34 may be applied to the disk 32 and the eccentric ring 40 may be then applied thereto.

Alternatively, the ring 34 may be secured in the .ap'erture 44 of the disk 40 if desired. The arrangement is such that although the eccentric disks are of different diameters for the purpose above set forth, the two ec centric mechanisms impart identically the same throw or travel to the two piston rods 20 which are connected thereto.

Although for the means of illustration there has been shown only sliding cylindrical surfaces in the bearings between the eccentrics 30 and 32 and the eccentric rings 38 and 40, it will be appreciated that each of these cylindrical bearing surfaces -may have anti-friction bearing assemblies such as balls, rollers or the like or otherrantifriction surfaces applied thereto.

I The operation of this mechanism will be readily ,understood from a consideration of FIGURE 2. The position of the eccentrics is so timed with respect to the position of the pistons th'atwhen the piston at the right side. of the unit is on its power stroke and, moves towards the left, the crankshaft 12' and its eccentric disk 30 will be rotated in a clockwise direction assh-own by the arrow 50. At the" same time, theec'centric ring 38 will be rotated in a counterclockwise direction as shown by opposite sides of said shaft and in-alinement with each the arrow 52. Thetwo oppositely rotating eccentric and eccentric ring units will thus eifect rotation'ofthe drive shaft 12 while permitting the piston rod unit to maineccentric disk e ach pair of pistons having a rigidly connected piston rod extending therebetween, the mid-portion of each rod having a bearing chamber, an eccentric ring-received in each bearing chamber and being journaled on an eccentric disk, a bearing shell journ aled on the smaller eccentric disk and being journaled' in the tain a straight line motion across the axis of thisdri ve I shaft. The two units 30 and 38 byro-tating in opposite I I directions will obtain a counterbalancing' eifect for the mechanism. I I

Inthe embodiment of FIGURE 2, single-acting pistons .16 have beenillustrated in the cylinder units 14. However, the invention is equally applicable to an engine in which double-acting pistons are employed Thisrwill necessitate a somewhat different connection of the piston rods to the piston units in order to permit the obtaining ofpower impulses at both ends of each cylinder unit.

Referring to FIGURESA and' 5, it will be observed that the cylinderunits 60 are provided with spark plugs 62 at each end thereof with a piston unit 64 being dispose-d therebetween and being reciprocable toward-s and from each of the spark plug units. However, the opposite side walls of the cylinder units ,60 are necessarily provided with longitudinally extending slots 66 therethrcugh in order that a transversely, dispose-d,- piston pin 68 of each'of the pistons may -be reciprocable in these slots and project to the exterior of the cylinder. At

the exterior of the cylinder, the piston pins are connected to pairs of piston rod sections 70 which correspond to the single piston rod sections 22 of the preceding embodiment. The two sections 70 of each piston are bolted to complementary sectionsrof the opposite ;alined piston,

and are connected to the single eccentric mechanism I previously described The operation of thisform of the invention is identical to that previously described except that the cylinders are double-acting in that, charges are taken into and fired successively at opposite ends of each cylinder.

The foregoing is considered aslillustrative'only of the.-

Further, since numerous principles of the invention. I modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction "and operation shown and described, and accordingly all suitable modifications. and

equivalents may be resorted to, falling within the scope least I two longitudinally spaced pairs of horizontal. alined cyl inders and pistons on opposite sides of adrive shaft and with the oppositely alined pistonbeing rigidly connected to a common piston rod whose mid-portionisconnected to said drive shaft, the improvement. comprising apair of eccentric disk-s of different diameters'fiznzdly mounted in longitudinal spaced position uponsaid drive shaft, a bearingsh-ell having an external diameter equ'al u-to tively one on said larger eccentric disk and the other on said smaller eccentric disk and the bearing shell thereon. I, 7 I V a 2. The'combination of claim 1 wherein each pistonrod comprises two sections each'rigidlylconn'ected atone end posed slot, piston pinseach-slidable' in a'slot and secured to a piston, said piston rod being disposedupon the exterior of saidicylinders and secured to the ends of said pistonpin. I

6. In an internal combustion engine having a drive shaft,

pairs of opposed cylinders spaced longitudinally of said drive shaft withwthe cylinders of each pair being axially aligned'in diametrically opposed relation on -opposite sides of said drive shaft,

. 'a' piston sl idably reciprocable in each cylinder,

. a rigid piston rod foreach pair of aligned pistons with the outer ends of said rod being secured to each of said pair ofpistons and maintaining the latter in fixedly spaced relation, "1

an eccentric mechanism for each piston rod detachably I connecting a mid portion ofthe'latter to said drive shaft and converting reciprocationof saidpiston to rotation of said drive shaft, eacheccentric mechanism, comprising aneccentr'ic disk fixed to said "drive shaft and an eccentric chamber in the associated piston rod mid-portion together, with an eccentric; ring mounted in the associated eccentriccharnber and mount-ed upon the associated eccentric disk, 1

a, bearing shell detachably journaled on one of said eccentric rings and detachably journaled upon one of the eccentric disks and eccentricchambers of the I associated eccentric mechanism,

one of the: eccentric disks, eccentric rings and eccentricrhousin-gsof one" of said eccentric mechanism being ofa ditferent sizefrom the corresponding element of the other eccentric mechanisms while the correspondingremaining elements of all of said eccentric mechanism are of the .same size whereby upon removal of said bearing shell all of the piston rod, may be slid axially diet and. onto said drive shaft from one :end thereof.

I 7. The combination of claim 6 wherein said one element of Jdifl ferent size is oneofsaid eccentric disks which is of smaller diameter than the other eccentric disks, for eccentric rings of allof the diife-rent eccentric mechanisms having a common 'external diameter and a common internal diameter.

' References Citedby the Examiner; I I UNITED. STATES PATENI-S I 1,705,638 3/29 Dua'B ose ;1123-56 2,132,595 210 325; Bancroft 123-56 I 2,288,963 7/421 Von Tavel 74- -49 2,310,733 I 2/43 Duke Q 123-56 B.' ,WII,KINSON, -Primqry Examiner. 

1. IN AN INTERNAL COMBUSTION ENGINE HAVING AT LEAST TWO LONGITUDINALLY SPACED PAIRS OF HORIZONTAL ALINED CYLINDERS AND PISTONS ON OPPOSITE SIDES OF A DRIVE SHAFT AND WITH THE OPPOSITELY ALINED PISTON BEING RIGIDLY CONNECTED TO A COMMON PISTON ROD WHOSE MID-PORTION IS CONNECTED TO SAID DRIVE SHAFT, THE IMPROVEMENT COMPRISING A PAIR OF ECCENTRIC DISKS OF DIFFERENT DIAMETERS FIXEDLY MOUNTED IN LONGITUDINAL SPACED POSITION UPON SAID DRIVE SHAFT, A BEARING SHELL HAVING AN EXTERNAL DIAMETER EQUAL TO THAT OF THE LARGER ECCENTRIC DISK DISPOSED UPON THE SMALLER ECCENTRIC DISK, A PAIR OF ECCENTRIC RINGS EACH JOURNALED IN THE MID-PORTION OF A PISTON ROD AND JOURNALED RESPECTIVELY ONE ON SAID LARGER ECCENTRIC DISK AND THE OTHER ON SAID SMALLER ECCENTRIC DISK AND THE BEARING SHELL THEREON. 